Careful what you touch! A computer is on display at Apple headquarters in Cupertino, California, US, on Aug. 7, 2007.小心你接觸的東西！去年八月七日，一台在美國加州庫比提諾的蘋果電腦總部展示的電腦。照片：歐新社

PHOTO: EPA

Do you ever surf the Internet while having a snack? You might want to think about washing your hands before you eat.

Computer keyboards can house millions of bacteria, a study has shown. Some keyboards have more filth on them than the average toilet seat.

A scientist in England examined samples from 33 keyboards and found a variety of germs. The germs can cause diarrhoea and vomiting.

The scientist checked a lavatory seat and a toilet door handle for comparison. One of the keyboards in the experiment was five times dirtier than the toilet seat. The keyboard was home to 150 times the acceptable limit of bacteria.

“I haven’t seen a reading like that in a very long time — it was off the scale,” said James Francis, the scientist.

The research showed that the main reason for the bacteria was people eating at their desks. Crumbs that are dropped can land between keys and encourage the growth of millions of bacteria.

Another cause was poor. For example, some people don’t wash their hands after going to the bathroom then use their computers.